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path: root/src/runtime/sigqueue_plan9.go
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* all: separate doc comment from //go: directivesRuss Cox2022-04-051-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | A future change to gofmt will rewrite // Doc comment. //go:foo to // Doc comment. // //go:foo Apply that change preemptively to all comments (not necessarily just doc comments). For #51082. Change-Id: Iffe0285418d1e79d34526af3520b415a12203ca9 Reviewed-on: https://go-review.googlesource.com/c/go/+/384260 Trust: Russ Cox <rsc@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>
* runtime, syscall: reimplement AllThreadsSyscall using only signals.Michael Pratt2022-02-151-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In issue 50113, we see that a thread blocked in a system call can result in a hang of AllThreadsSyscall. To resolve this, we must send a signal to these threads to knock them out of the system call long enough to run the per-thread syscall. Stepping back, if we need to send signals anyway, it should be possible to implement this entire mechanism on top of signals. This CL does so, vastly simplifying the mechanism, both as a direct result of newly-unnecessary code as well as some ancillary simplifications to make things simpler to follow. Major changes: * The rest of the mechanism is moved to os_linux.go, with fields in mOS instead of m itself. * 'Fixup' fields and functions are renamed to 'perThreadSyscall' so they are more precise about their purpose. * Rather than getting passed a closure, doAllThreadsSyscall takes the syscall number and arguments. This avoids a lot of hairy behavior: * The closure may potentially only be live in fields in the M, hidden from the GC. Not necessary with no closure. * The need to loan out the race context. A direct RawSyscall6 call does not require any race context. * The closure previously conditionally panicked in strange locations, like a signal handler. Now we simply throw. * All manual fixup synchronization with mPark, sysmon, templateThread, sigqueue, etc is gone. The core approach is much simpler: doAllThreadsSyscall sends a signal to every thread in allm, which executes the system call from the signal handler. We use (SIGRTMIN + 1), aka SIGSETXID, the same signal used by glibc for this purpose. As such, we are careful to only handle this signal on non-cgo binaries. Synchronization with thread creation is a key part of this CL. The comment near the top of doAllThreadsSyscall describes the required synchronization semantics and how they are achieved. Note that current use of allocmLock protects the state mutations of allm that are also protected by sched.lock. allocmLock is used instead of sched.lock simply to avoid holding sched.lock for so long. Fixes #50113 Change-Id: Ic7ea856dc66cf711731540a54996e08fc986ce84 Reviewed-on: https://go-review.googlesource.com/c/go/+/383434 Reviewed-by: Austin Clements <austin@google.com> Trust: Michael Pratt <mpratt@google.com> Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
* os/signal: fix a deadlock with syscall.AllThreadsSyscall() useAndrew G. Morgan2020-12-231-0/+7
| | | | | | | | | | | | | | | The syscall.AllThreadsSyscall() fixup mechanism needs to cooperate with signal handling to ensure a notetsleepg() thread can wake up to run the mDoFixup() function. Fixes #43149 Change-Id: I6651b25bc44a4de47d3fb71d0293d51aef8b79c7 Reviewed-on: https://go-review.googlesource.com/c/go/+/277434 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Trust: Austin Clements <austin@google.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
* os/signal, runtime: remove runtime sigqueue initializationIan Lance Taylor2020-04-011-4/+1
| | | | | | | | | | We can initialize the runtime sigqueue packages on first use. We don't require an explicit initialization step. So, remove it. Change-Id: I484e02dc2c67395fd5584f35ecda2e28b37168df Reviewed-on: https://go-review.googlesource.com/c/go/+/226540 Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Bryan C. Mills <bcmills@google.com>
* os/signal: add func Ignored(sig Signal) boolAdam Azarchs2018-04-211-0/+5
| | | | | | | | | | | | | | | | Ignored reports whether sig is currently ignored. This implementation only works applies on Unix systems for now. However, at the moment that is also the case for Ignore() and several other signal interaction methods, so that seems fair. Fixes #22497 Change-Id: I7c1b1a5e12373ca5da44709500ff5acedc6f1316 Reviewed-on: https://go-review.googlesource.com/108376 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
* os/signal: avoid race between Stop and receiving on channelIan Lance Taylor2017-06-241-0/+20
| | | | | | | | | | | | | | | | When Stop is called on a channel, wait until all signals have been delivered to the channel before returning. Use atomic operations in sigqueue to communicate more reliably between the os/signal goroutine and the signal handler. Fixes #14571 Change-Id: I6c5a9eea1cff85e37a34dffe96f4bb2699e12c6e Reviewed-on: https://go-review.googlesource.com/46003 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
* all: single space after period.Brad Fitzpatrick2016-03-021-1/+1
| | | | | | | | | | | | | | | | | | | | The tree's pretty inconsistent about single space vs double space after a period in documentation. Make it consistently a single space, per earlier decisions. This means contributors won't be confused by misleading precedence. This CL doesn't use go/doc to parse. It only addresses // comments. It was generated with: $ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])') $ go test go/doc -update Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7 Reviewed-on: https://go-review.googlesource.com/20022 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Dave Day <djd@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
* runtime, os/signal: use //go:linkname instead of assembly stubs to get ↵Michael Hudson-Doyle2015-10-161-0/+6
| | | | | | | | | | | | | | | | | | access to runtime functions os/signal depends on a few unexported runtime functions. This removes the assembly stubs it used to get access to these in favour of using //go:linkname in runtime to make the functions accessible to os/signal. This is motivated by ppc64le shared libraries, where you cannot BR to a symbol defined in a shared library (only BL), but it seems like an improvment anyway. Change-Id: I09361203ce38070bd3f132f6dc5ac212f2dc6f58 Reviewed-on: https://go-review.googlesource.com/15871 Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Minux Ma <minux@golang.org> Reviewed-by: Dave Cheney <dave@cheney.net>
* runtime: fix signal handling on Plan 9David du Colombier2015-05-121-7/+16
| | | | | | | | | | | | | Once added to the signal queue, the pointer passed to the signal handler could no longer be valid. Instead of passing the pointer to the note string, we recopy the value of the note string to a static array in the signal queue. Fixes #10784. Change-Id: Iddd6837b58a14dfaa16b069308ae28a7b8e0965b Reviewed-on: https://go-review.googlesource.com/9950 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
* os/signal: add ability to ignore signals and restore initial signal handlersMichael MacInnis2015-02-161-0/+4
| | | | | | | | | | | | | | There is currently no way to ignore signals using the os/signal package. It is possible to catch a signal and do nothing but this is not the same as ignoring it. The new function Ignore allows a set of signals to be ignored. The new function Reset allows the initial handlers for a set of signals to be restored. Fixes #5572 Change-Id: I5c0f07956971e3a9ff9b9d9631e6e3a08c20df15 Reviewed-on: https://go-review.googlesource.com/3580 Reviewed-by: Ian Lance Taylor <iant@golang.org>
* os/signal, runtime: implement notes on Plan 9David du Colombier2015-02-061-0/+115
This change is an implementation of the signal runtime and os/signal package on Plan 9. Contrary to Unix, on Plan 9 a signal is called a note and is represented by a string. For this reason, the sigsend and signal_recv functions had to be reimplemented specifically for Plan 9. In order to reuse most of the code and internal interface of the os/signal package, the note strings are mapped to integers. Thanks to Russ Cox for the early review. Change-Id: I95836645efe21942bb1939f43f87fb3c0eaaef1a Reviewed-on: https://go-review.googlesource.com/2164 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Rob Pike <r@golang.org>